This invention relates generally to network management.
Enterprises have internal networks (intranets) that handle communications throughout an entire geographically dispersed organization. Managing such networks is increasingly costly, and the business cost of network problems increasingly high. Managing an enterprise network involves a number of inter-related activities including establishing a topology, establishing a policy and monitoring network performance. Network topology can have a significant impact on the cost of building a network and on the performance of the network once it has been built. An increasingly important aspect of topology design is network segmentation. In an effort to provide fault isolation and mitigate the spread of worms, enterprises segment their networks using firewalls, routers, VLANs and other technologies. In a network different users have different privileges. Some users have unlimited access to external networks while other users have highly restricted access. Some users may be limited in the amount of bandwidth they may consume on particular routes, and so on. The number of policies is open ended. Operators also monitor network performance. Almost every complex network suffers from various localized performance problems. Network managers detect these problems and take action to correct them.
Another aspect of network management is detecting and dealing with security violations. Increasingly, networks are coming under attack. Sometimes the targets are chosen at random (e.g., most virus-based attack). Sometimes the targets are chosen intentionally (e.g., most denial of service attacks). These attacks often involve compromised computers within the enterprise network. Early detection of attacks plays a critical role in reducing damage to networks and systems coupled to the networks.